An amount of 1 mole of a non volatile binary electrolyte AB is dissolved in 100 moles of water. This solution has freezing point 271.5 K. Identify the correct informations ( $K_f$ of water= $1.8K.kg.mo{l}^{-1},$ freezing temperature of pure water is 273 K, degree of ionization of AB remain same at all temperatures)

The degree of dissociation of AB is 0.5

If the solution is cooled up to -2°C then nearly 450 g of ice separated from the solution

If vapour pressure of pure water at 373 K is 760 mm of Hg then vapour pressure of given solution is 752.4 mm of Hg at same temperature

The ratio of normal molar mass to abnormal molar mass of AB is 1.5